Replace your public email with an inbox that pays you.

The 21 app allows you to earn bitcoin in exchange for answering messages and completing tasks. Users set up a 21.co public profile, enabling others to send messages and tasks to the user without revealing personal contact information. After answering a message or completing a task, you will receive a task reward in bitcoin.

21 allows you to replace your public email with an inbox that pays you. The idea is that you set up a 21 profile (like 21.co/naval) and people outside your network can now pay to contact you. You can keep the money or donate it to charity. It's like LinkedIn InMail, except you actually get paid :) And we use bitcoin under the hood, so it works in any country.
You can sign up for a profile and answer messages on either web (at 21.co) or mobile (at ios.21.co).
Note that "answering a message" is only the simplest task that the 21 webapp and app support. You can also complete surveys and do more complex things. You will see one of these surveys in the tutorial when you boot up the app; more are coming. But right now, the primary source of tasks will be paid messages to you from people outside your network. And the simplest way to solicit more such messages is to put your 21.co profile link on your homepage or Twitter bio, like this or this.

@balajis Everyone here would have complimented the idea behind the product and its implementation - no doubt 21.co is the first of its kind that helps you avoid the spam that is generated on day-to-day basis and at the same time that provides you 'quality' connects and potential network of wonderful people.
Here is something no one else would have told you: The combination of Black and Gold looks awesome - especially on an iPhone. :-)
Kudos to the 21.co team @balajis :-)

@balajis Super! logged in via facebook, created username, verified email, had prompt to login again, did so, login window persists... am logged in and can click other tabs but that initial empty state is confusing IMHO. Looking forward to using this and adding other nonprofits 👏

@nickabouzeid Yup! Right now we support Black Girls Code and Folding@Home, but we'll be adding more over time. If you have ideas on what we should add, we set up a quick form at nonprofits.21.co that you can fill out.

@nhuebecker@chadwhitaker Right now, you can email verify@21.co and we'll take care of you. As context, we've had a crush of signups recently and are working hard on streamlining the process. Starting next week, verification will be integrated with signup on both web & mobile, and we will give you a timeline on how long verification will take (it should be quick once that's up and running).